CHAPTER XXVIII. 



ELECTRICAL PRODUCTS CALCIUM CARBIDE. 



Another important use to which electricity 

 is put at Niagara Falls is the manufacture of 

 a new product, called calcium carbide. Like 

 carborundum and aluminum, this product 

 could not have been produced in commercial 

 quantities in advance of a means for pro- 

 ducing electricity in enormous volume. 



Calcium carbide is a compound of calcium 

 and carbon. Calcium is a white metal not 

 found in the natural state, but exists chiefly 

 as a carbonate of lime, which is ordinary lime- 

 stone, including the various forms of marble. 

 As a pure metal it is hard to obtain and very 

 hard to maintain, as it readily oxidizes when 

 in contact with the air. The symbol for cal- 

 cium carbide is CaC 2 , which means that a 

 molecule of this carbide is compounded of one 

 atom of calcium and two atoms of carbon. 

 Ca stands for calcium and C for carbon. When 

 the symbol has no figure following it, it means 

 that one atom only enters into the compound; 

 but if a figure follows, it means that as many 

 atoms enter in as the figure represents. 



